1. Field of the Invention
The present invention relates to methodology and apparatus for monitoring, analyzing and displaying large amounts of physiological data or waveforms, and in particular relates to the methodology and apparatus for monitoring, analyzing and displaying ambulatory ECG waveforms.
2. Description of the Prior Art
Video analysis systems for monitoring, analyzing and displaying ECG waveforms were pioneered by Holter et al., examples of which is shown in Holter, U.S. Pat. No. 3,215,136 and U.S. Pat. No. 3,229,687. These types of prior art devices attempted to superimpose multiple ECG signals one on top of the other to facilitate the detection of an abnormal ECG waveform as compared to a plurality of normal waveforms.
Subsequent to these early monitoring and display devices, assignee of the present invention developed video display units capable of presenting a plurality of ECG signals in a two dimensional array on a cathode ray tube, for example see Cherry, U.S. Pat. No. 4,006,737; Cherry et al., U.S. Pat. No. 4,073,011; and U.S. Pat. No. 4,123,785. More recently practitioners in the field have developed an automated system for displaying ECG waveforms read at an accelerated rate from a tape deck in a two dimensional format on a CRT display wherein two channels of information are read and multiplexed upon the display, see for example Gessman, U.S. application Ser. No. 74,475 now issued. However, such prior art devices are able to produce multiple channels of ECG waveform in a CRT display with poor fidelity. Moreover, the flexibility of such prior art systems with respect to annotating and marking abnormal beats in the display are severely limited.
What is needed are improvements to such prior art systems which will generate high fidelity reproductions of multiple channels of ECG waveforms read at accelerated rates from a storage media, such as magnetic tape, which allows not only for increased flexibility and capability with respect to annotation and marking of the displayed waveforms, but inherently allows a greater flexibility and user control of a plurality of display formats.